Listeria

Question 1

medically most important

Answer 1

L monocytogenes

Question 2

gram, shape, respiration, spore, catalase, where in cell, motility, hemolysis, salt, temperature

Answer 2

-gram positive
-rod, bacilli
-facultative anaerobe
-non spore forming
-catalase positive
-intracellular pathogen
-flagella for motility and invasion
-beta hemolytic on blood agar
-resistant to high salt
-grow at cold (4 C) temperatures

Question 3

motility shape thing

Answer 3

umbrella shaped colony – tumbling motility

Question 4

most frequently isolated form food serotype

Answer 4

1/2a

Question 5

majority of human epidemics serotype

Answer 5

4b

Question 6

3 most important serotypes – virulent

Answer 6

1/2a
1/2b
4b

Question 7

culture media for growth

Answer 7

-mullen hinton agar with 5% sheep blood – beta hemolytic
-fastidious bacteria
-grow very slowly

Question 8

issues with isolation of listeria

Answer 8

-requires enrichment media
-requires prolonged incubation time

Question 9

improved culture for listeria isolation

Answer 9

-FDA BAM enrichment broth
-ISO 11290 enrichment broth

Question 10

listeria is adaptive

Answer 10

-resistant to high salt
-survive and multiply on inanimate objects
-adapt to changing temperatures

Question 11

habitat

Answer 11

-saprophytes in soli and decaying vegetation
-abundant in cold temperatures

Question 12

host ranges

Answer 12

-diverse range of hosts
-more common in ruminants (mainly sheep)
-foodborne pathogen in humans

Question 13

transmission

Answer 13

-entry – ingestion
-feeding sialge with high iron content
-exit – feces, vaginal discharge, milk

Question 14

body strucutres

Answer 14

-flagella for motility, adhesion, invasion
-internalin (A, B, C) for adhesion, invasion
-form biofilms
-intracellular pathogen

Question 15

enzymes – superoxide dismutase

Answer 15

-protects listeria against free radicals from host phagocytic cells

Question 16

enzymes – phospholipase

Answer 16

-pore forming lysis in endocytosis membrane of host cell to free self from lysosome (vacuoles)

Question 17

toxins – beta hemolysin

Answer 17

-pore forming lysis in endocytosis membrane of host cell to free self from lysosome (vacuoles)

Question 18

toxins – listeriolysin O

Answer 18

-pore forming lysis in endocytosis membrane of host cell to free self from lysosome (vacuoles)

Question 19

toxins – bacteriocins (listeriolysin S)

Answer 19

-kill competing gut microbiota

Question 20

toxins – actin polymerizing protein (actA)

Answer 20

-deposition of host cell actin filaments on end of listeria
-listeria uses host cell actin filaments to propell

Question 21

barriers listeria can enter

Answer 21

-cell membrane lipid bilayer barrier
-intestinal barrier
-placental barrier
-blood brain barrier

Question 22

pathogeensis of listeria

Answer 22

-attachment and adhesion
-intracellular invasion
-intracellular multiplication
-spread to other cells

Question 23

surfcae proteins of listeria and host epithelium

Answer 23

listeria – intermalin
host epithelium – E-CADHERIN

Question 24

listeriosis

Answer 24

-febrile gastroenteritis
-septicemia, shock
-placentitis
-brainstem and cranial nerve dysfunction

Question 25

neural form of listeriosis

Answer 25

-in silage fed to sheep
-microabscesses in brain
-ataxia and circling disease
-unilateral facial paralysis

Question 26

visceral form of listeriosis

Answer 26

-speticemia
-gastroenteritis
-liver nad spleen damage
-fetoplacental tropism (abortion)
-myocarditis
-osteomyelitis
-mastitis

Question 27

treatment

Answer 27

-ampicillin
-chlortetracycline
-penicillin
-trimethoprim sulfamethoxazole

Question 28

control

Answer 28

-difficult – exist everywhere
-risk factors not well known
-vaccines – live attenuated (Norway), commercial killed (some ocuntries)

Question 29

frank pathogen

Answer 29

-will always cause disease
-body starts fighting it as soon as it enters

Question 30

intracellular pathogen?

Answer 30

yes

Question 31

predilection site

Answer 31

visceral and neural infection